use raw pointer of table in class column (progress, needs fixes in tests)

source/orm/orm/session_query_builder.cpp

@@ -44,7 +44,7 @@ void criteria_transformer::update_criteria_column(const query::abstract_column_c
         return;
     }
 
-    const_cast<query::column&>(node.col()).table(it->second);
+    const_cast<query::column&>(node.col()).table(it->second.get());
 }
 
 void session_query_builder::on_revision(const char *id, uint64_t &/*rev*/) {
@@ -56,7 +56,7 @@ void session_query_builder::push(const std::string &column_name) {
   if (it == processed_tables_.end()) {
     throw query_builder_exception{query_build_error::UnexpectedError};
   }
-  entity_query_data_.columns.emplace_back(it->second, column_name, build_alias('c', ++column_index));
+  entity_query_data_.columns.emplace_back(it->second.get(), column_name, build_alias('c', ++column_index));
 }
 
 std::string session_query_builder::build_alias(const char prefix, const unsigned int count) {

source/orm/query/column.cpp

@@ -18,7 +18,7 @@ column operator ""_col(const char *name, const size_t len) {
     throw std::invalid_argument("Invalid column name: multiple dots found");
   }
 
-  return column{std::make_shared<table>(str.substr(0, pos)), str.substr(pos + 1)};
+  return column{new table(str.substr(0, pos)), str.substr(pos + 1)};
 }
 
 column::column(const char *name, const std::string& as)
@@ -26,17 +26,15 @@ column::column(const char *name, const std::string& as)
 {}
 
 column::column(std::string name, std::string as)
-: table_(std::make_shared<query::table>())
-, name_(std::move(name))
+: name_(std::move(name))
 , alias_(std::move(as)) {}
 
 column::column(const sql::sql_function_t func, std::string name)
-: table_(std::make_shared<query::table>())
-, name_(std::move(name))
+: name_(std::move(name))
 , function_(func) {}
 
-column::column(const std::shared_ptr<query::table>& t, std::string name, std::string as)
-: table_(t)
+column::column(const class table* tab, std::string name, std::string as)
+: table_(tab)
 , name_(std::move(name))
 , alias_(std::move(as)) {
 }
@@ -85,12 +83,12 @@ bool column::has_alias() const {
   return !alias_.empty();
 }
 
-std::shared_ptr<table> column::table() const {
+const class table* column::table() const {
   return table_;
 }
 
-void column::table( const std::shared_ptr<query::table>& t ) {
-  table_ = t;
+void column::table(const query::table* tab) {
+  table_ = tab;
 }
 
 column::operator const std::string&() const {